The internet is by its very definition, public. It was created almost
entirely by its users, in order to fulfil their needs. Central to the
very concept of the internet is that EVERYONE (even the poor, the
politically oppressed) has access to it at least in principle.
By allowing royalty collecting patents to be considered "standards" the
W3C clearly puts that in jeopardy - because if royalties are charged at
anything other than an infinitesimal level, only large groups
(essentially only large corporations) will be able to implement internet
technologies. That means that all the current community based, free (in
the sense of both free speech and a free lunch) elements of the internet
will be crippled. No longer can just anyone run the free Apache web
server, or the free Mozilla browser, or the free KDE desktop, or in fact
anything else that is free, without losing access to an important
portion of the internet.
So essentially what this threatens to do is to remove the free,
community based infrastructure of the internet, replacing it with a
shallow corporate intranet, where large software manufacturers have
almost complete control over what people can and cannot do. The W3C,
set-up to stop this from happening, clearly must not allow this.